A monowheel is a sort of car that rides on a single wheel. Chances are you’ll suppose that sounds so much like a unicycle or a Onewheel-style electrical skateboard, however the distinguishing characteristic of a monowheel is its large diameter. A conventional monowheel car carries its rider inside the center, the place the hub can be. Within the case of smaller robots, the motor and the entire digital parts sit inside the circle of the rim. However like a unicycle, it’s onerous to maintain a monowheel upright whereas transferring slowly or standing nonetheless. To skirt that challenge, James Bruton constructed a mechanically secure monowheel robotic.
Calling this a “monowheel” is a little bit of a cheat, as a result of it technically has two wheels — they’re simply very shut collectively. The usage of two wheels comes with benefits. First, it lets the robotic steadiness in place with out tipping to both aspect. Second, it makes steering easy. Like a tank, this robotic has differential drive: spin one wheel sooner than the opposite and it’ll flip. It might probably even rotate in place if the wheels spin in reverse instructions.
However the huge innovation right here is the kind of wheels that Bruton selected. Every of these is a pedrail wheel, which is a wierd contraption with a complete bunch of sliding legs in a radial association with pivoting ft. It rotates like a wheel, however retains at the least a number of ft involved with the bottom at any given time. Not solely does that assist it traverse sure obstacles, like steps, but it surely additionally means the pedrail wheel can stay stationary with out rolling forwards or backwards.
Bruton 3D-printed nearly the entire mechanical components for this robotic, together with the legs and ft. The one components that weren’t 3D-printed have been the fasteners and bearings. Due to the distinctive drive system, this robotic’s electronics are fairly easy — no IMU (inertial measurement unit), gyroscope, or accelerometer mandatory. There are two DC motors that spin the wheels and a Teensy 3.2 improvement board controls these. It receives instructions from Bruton’s common distant through OrangeRX DSM transceivers.
Testing proved that this idea works pretty nicely. The robotic strikes round simply and might stay nonetheless with none type of lively balancing. It might probably additionally climb over small obstacles, although the top-heavy nature of the design makes it considerably unstable if uneven terrain causes it to tip to both aspect. Spacing the wheels additional aside would clear up that challenge, however then it might be even more durable to categorise this robotic as a monowheel.
